The invention generally relates to network technology, and more particularly relates to Local Area Network (LAN) technology.
The proliferation of personal computers as a business tool throughout organizations such as corporations, institutions, and others triggers a requirement to provide communications capability between these computers as well as between different types of computers. In general, through the installation of an adapter card in each personal computer, cabling, software, and special computers known as servers, Local Area Networks (LANs) can be set up. This type of network allows persons within a localized geographical area such as a building or campus to communicate with each other, share peripheral devices such as printers, and to have access to software programs and database information residing on servers. By linking these LANs together, a Wide Area Network (WAN), such as what is commonly known as the Internet, can be created.
There are several LAN technologies in use today with Ethernet (a.k.a. IEEE 802.3 and its derivatives) being far the most popular LAN technology due to its openness, ease of use, robustness, and reliability. Essentially, for Ethernet LANs, access to the shared medium (e.g., twisted pair wires, coaxes, fiber optics, etc.) is controlled by a media access control (MAC) mechanism embedded in the Ethernet interface adapter card located at each station. The MAC is controlled by the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Protocol.
While originally envisioned as a shared COAX broadcast network, it has evolved into a twisted pair (TP) based point-to-point network with hub devices handling the interconnections between nodes known as 10baseT (for the 10 megabit transfer rate version) or 100baseT (for the 100 megabit transfer rate version). To function properly, these TP based LAN schemes have specific requirements such as wire electrical characteristics and maximum allowable wire lengths. Accordingly, if the length of a TP wire exceeds the allowable wire length specified or if the wire characteristics do not meet the requirements specified, the Ethernet LAN connection may be undependable or may not even be operable. On the other hand, if a wire exceeds these requirements, the Ethernet LAN connection can not perform beyond its rated maximum throughput.
Demands for applications requiring high bandwidth and high data throughput such as video conferencing, on-demand video download, and others continue to increase. At the same time, communications between high performance servers on an Ethernet LAN also require very high data throughput. These demands often exceed the optimal available network throughput in conventional Ethernet LANs. Ethernet LANs with greater than the normal operating distance are also in demand. As a result of the demands for greater operating distance and throughput, secondary networking technologies are adopted in Ethernet LANs. An example of the secondary networking technologies is the use of Fiber Optics instead of wire. However, the adoption of a non-Ethernet solution carries with it a variety of added burdens and costs.
Furthermore, in normal operations, 10baseT and 100baseT Ethernet LANs are subject to a host of problems. One common problem involves imperfect connections between computers due to loose or broken cables that are caused by human abuse, furniture pinching, normal office wear-and-tear, and others. In conventional Ethernet LANs, the attached computer is cut off from the network even if only a single conductor loses continuity.
Thus, a need exists for a method, apparatus, and system to provide an open, easy-to-use, robust, and reliable LAN that is capable of handling high data throughput and high bandwidth communication applications and at the same time, is adaptive to changing conditions to allow for gradual degradation.
Accordingly, the present invention provides a method, apparatus, and system to provide an open, easy-to-use, robust, and reliable a Local Area Network (LAN) that is capable of handling high data throughput and high bandwidth communication applications and at the same time, is adaptive to changing conditions to allow for gradual degradation and open for future enhancements.
The present invention meets the above need with a LAN interface adapter apparatus that comprises: an interface circuit coupled between a data terminal device and a LAN, a transmit circuit coupled to the interface circuit, and a receive circuit coupled to the interface circuit. The LAN interface adapter apparatus is compatible to present-day 10baseT and 100baseT and optionally 1000base T LANs.
The interface circuit performs a network initialization process with another data terminal device having a substantially similar interface adapter apparatus coupled to the LAN prior to a data transfer between the two devices. The network initialization process determines information related to available data throughput, optimized bandwidth, optimized transfer conditions, and electrical characteristics of a connection between the devices. Optionally, the interface circuit further encrypts data for transmission and decodes encrypted data received. The transmit circuit utilizes the information determined from the network initialization process for transmitting data. The receive circuit utilizes the information determined from the network initialization process for receiving data.
If using encryption, the network initialization process also determines a session key for use in decoding encrypted data. The network initialization process further determines which one of the two data terminal devices is designated a Data Terminal Equipment (DTE) and which device is designated a Data Communication Equipment (DCE). The electrical characteristics of the connection between the devices are used to make adjustments and compensations on a data signal from the DTE to obtain a desired data signal at the DCE. Transmitting and receiving data are formatted in data frames such that each data frame is made up of multiple data packets. The initialization process also provides a framework for future enhancements.